C?A/600/2-89/042
July 1989
IN SITU BIOREMEDIATION OF SPILLS FROM UNDERGROUND STORAGE TANKS:
NEW APPROACHES FOR SITE CHARACTERIZATION
PROJECT DESIGN, AND EVALUATION OF PERFORMANCE
by
John T. Wilson and Lowell E. Leach
U.S. Environmental Protection Agency
Joseph Michalowski, Steve Vandegrift, and Randy Callaway
N.S.l. Technology Services, Inc.
Project Officer
John T* Wilson
Subsurface Processes Branch
Robert S. Kerr Environmental Research Laboratory
Ada, Oklahoma 74820
ROBERT S. KERR ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
ADA, OKLAHOMA 74820
»
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DISCLAIMER
The information in this document has been funded wholly or m part
by the United States Environmental Protection Agency under 68-C8-0025
to NS1. It has been subject to the Agency's peer and aormnistrative
review, and ic has been approved for publication as an EPA document.
11
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FOREWORD
EPA charged by Congress to protect the Nation's land,
air and water systems. Under a mandate of national environmental
laws focused on air and water quality, solid vaste management and
the control of toxic substances, pesticides, noise and radiation,
the Agency strives to formulate and implement actions which lead
to a compatible balance between human activities and the ability
of natural systems to support and nurture life.
The Robert S. Kerr Environmental Research Laboratory is the
Agency's center of expertise for investigation of the soil and
subsurface environment. Personnel at the Laboratory are respon-
sible for management of research programs to: (a) determine the
fate, transport and transformation rates of pollutants in the
soil, the unsaturated and the saturated zones of the subsurface
environment; (b) define the processes to be used in characteri-
zing the soil and subsurface environment as a receptor of pol-
lutants; (c) develop techniques for predicting the effect of
pollutants on ground water, soil, and indigenous organisms; and
(d) define and demonstrate the applicability and limitations of
using natural processes, indigenous to the soil and subsurface
environment, for the protection of this resource.
Tnis report presents a systematic approach for the design
of in situ bioremediation of hydrocarbon contamination in ground
water from the determination of the total quantity of hydro-
carbons in the aquifer to the utilization of that information in
an actual field bioremediation demonstration.
4/, -j'rt O
Clinton W. Hall
Director
Robert 5. Kerr Environmental
Research Laboratory
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TA3LE OF CONTENTS
Page
INTRODUCTION 1
S-CTION I. sit: characterization for in situ bioremediation
OF HYDROCARBON LEAKS FROM UNDERGROUND STORAGE TANKS 4
SECTION II. PROCEDURE FOR ACQUIRING CORE SAMPLES 9
SECTION III. PROCEDURES TO DETERMINE THE CONCENTRATION
OF CONTAMINANTS 20
StCriON IV. FIELD DEMONSTRATION OF SAMPLING AND ANALYTICAL
PROCEDURES IN DESIGNING A BIOREMEDIATION 31
REFERENCES 56
V
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INTRODUCTION
"I"his report presents a systematic approach for the design of in situ
bioremediation of hydrocarbon contamination in ground water from the
determination of the total quantity of hydrocarbons in the aquifer to the
utilization of that information --n an actual field bioremediation demon-
stration.
Bi oreriedi ati on of ground water contaminated with hydrocarbons such
as gasoline is an on-site treatment technology that is both potentially
technically feasible and more cost-effective than Mpump and treat"
technologies which involve pumping of contaminated ground water to the
surface and removal of the contarr.inant by air-stripping or carbon adsorp-
tion. In situ bioremediation usually consists of modifying the environ-
ment of an aquifer by the addition of oxygen and other inorganic nutrients
in order to enhance the activity of native microbial populations in
degrading contaminants. Bioremediaticn is especially promising with
hydrocarbons which are potentially biodegradable by native subsurface
bacteria under the right environmental conditions to harmless byproducts.
Successful biorernediation is dependent upon a number of factors,
including the hydrogeology at the site and the availability of critical
nutrients in the aquifer. The primary limiting fac'.or with hydrocarbons
is the availabilty of oxygen. If sufficient oxygen is not present
naturally, then oxygen wjst be provided by circulating oxygenated water
through the contaminated area until degradation is complete.
The primary factor which determines how much oxygen and nutrients
must be supplied to a hydrocarbon leak and how long remediation will take
is the quantity of the hydrocarbon at the site. Normally, the amount of
the 1 ek is not
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contaminant at the site and it's location are not acceptable.
Almost all techn ques that have been applied for the analysis of
oily contannr.ants in aquifers emphasize the compounds of regulatory
interest, and fsw a^e appropriate for both solids and water. All too
frequently, the or-1 y information available from a leak site is the
concentration of selected organic contaminants in water from wells.
Such information is inadequate for determining the total quantity of
hydrocarbons 1-1 the aquifer. Therefore, it is impossible to determine
how much oxygen and nutrients must be delivered to the aquifer to support
sufficient mcrobial activity to degrade all of the contaminant to harm-
less byproducts.
This report explains w'r\y tne total quantity of hydrocarbons in an
aquifer car only be determined by collecting cores. A procedure to
acquire co;*es from a cor.t'imin ited aquifer is described. Before the
procedure was developed, it was very difficult to recover good-auality
cores of unconsolidated "andy material from below the water table. The
report also describes two Drocadures to determine how much contamination
the cores contain. Results of the two procedures are in good agreement,
even though they are based on different principles.
The two techniques were developed and evaluated by scientists at
the Robert S. Kerr Environmental Research Laboratory as part of a
large biorenediation research program. An oi1-and-grease method was
adapted tc estimate total hydrocarbons in core samp'ies. A second method
was adapted rrom techniques for the analysis of fuels that determines the
total content of hydrocarbons as well as the specific content of indivi-
dual compounds of interest.
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Basically, the oi1-and-grease method uses infrared spectroscopy
to measure the absorbance of carbon-hydrogen chemical bonds. Quantitation
is sensitive to the type of hydrocarbon but is relatively insensitive to
the particular organic constituents of the fuel. In the fuel carbon
technique the hydrocarbons are extracted into methylene chloride,
then separated and quantified by gas chromatography. Representative
peaks are selected, 3nd the quantity of total hydrocarbons is calculated
by comparing the area of the representative peaks in a standard sample
of the fuel to the area of the same peaks in the extract. The method
works well if the standard is representative of the material being analyzed.
If the proper calibrations are done, the concentrations of compounds of
regulatory interest, such as the alkylbenzenes, can be determined in
the same analytical run. The techniques for core analysis and their
performance is discussed in Section III of this report.
The procedures described in the report were field-tested in designing
a demonstration of the bioremediation of an aviation gasoline leak.
The perfcrmaice of the demonstration was consistent with the expected
performance based on the preliminary site characterization us^ng the
described procedures.
3
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SECTION I. SITE CHARACTERIZATION FOR IN SITU BIOREMEDI ATION OF
HYDROCARBON LEAKS FROM UNDERGROUND STORAGE TANKS
Underground storage tanks have been installed in almost every possible
geological lithology; however, many of the known leaks from underground
storage tanks occur in unconsolidated material.
There are several reasons for this. Many of our inland cities are
built on floodplains or river terraces because they are flat and near
water. M*ior portions of our coastal cities are built on old beaches or
glacial outwash. Because these materials are transmissive, re1eas?s from
underground storage tanks drain readily into the water table. Ground-water
flow in these areas is usually rapid, and plumes of contamination can
spread ever wide areas in a short period of time. Unconfirmed aquifers
in sandy unconsolidated materials are commonly used for domestic water
supply. When there is a high density of wells, detecting a release is
much more likely.
The pattern of contamination from 3 leak is complex (Figure 1).
As the release drains through the unsaturated zone, a portion is left
behind trapped by caoillary forces. If che released material is volatile,
a plume of vapors soon forms in the soil ai** in the vadose zone. If the
release is a light hydrocarbon, it will dram down to the water table,
and then spread laterally. Ground water moving through the aquifer comes
in contact with the release, and leaches out the more water-soluble
components. As a result there are three distinct regions or "plumes"
formed at the leak site: a plume of volatile fumes in the soil air, a
ground-water plume, and the region primarily in the unsaturated zone
tnat contains the oily-phase material which serves as a source area for
both plumes.
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¦1
Leaking Underground
Storage Tank
Fumes
Fumes
\ Continuous
1 Phase
Residual
Saturation
Water
Table
Dissolved
Hydrocarbon
/ \ /
Figure 1. Regions of Contamination i,i a Typical Release from an Underground Storage Tank.
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In practice the source area is usually the object of remedial activi-
ties. .here is little point in treating the ground w-Her or vapors if
the source area is left to spread more contamina:ion. Therefore, the
first step is to remove any leaking tanks, trinsmission pipes, ar-d the
most visibly contaminated fill-material around the tank. Although necessary,
such practices usually do not remove all of the source. The material
trapped in the earth solids beneath the tank will remain
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For example, Section IV or this report demonstrates how comparisons
of ground water analyses vs. core analyses at an aviation gasoline spill
site in Michigan showed that the ground water analyses underestimated the
amount of toluene in the aquifer significantly. Further analysis showed
that the core contained petroleum hydrocarbons that sorted most of the
toluene. If the data from the monitoring well had been used to design a
remedy, the effort and expense required to restore the aquifer would have
been underestimated by a factor of six.
Obviously, the distribution of the source area and the extent of
contamination can only be characterized by collecting and analyzing
cores, because they sample the entire aquifer, not just the ground water.
Very precise information is needed on the vertical extent of contamination,
particularly for in situ biorestoration. The injected waters are very
expensive, and water injected into a clean part of the aquifer is wasted
(Figure 2). If injected water moves underneath the contaminated interval
and breaks through in a monitoring well, it can also give the false
impression that the region of aquifer between the two wells is clean.
Accurate techniques for analyzing cores to determine the total
quantity of petroleum hydrocarbons in the aquifer and the concentration
of individual compounds of regulatory concern are necessary not only for
estimating the ultimate demand for oxygon, but also for documenting at
the end of the remed'atior. that the clean-up is complete.
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Ir,jec::cn
Weil
v y
\
Lir.d Surfa
Water
Tade
^
=j C^> D'iroc!
^cniainnated E:
Interval
IT
i of Flow
¦=!> <=?>
lnj-:ct.on
Well
;_J£ Z
\
vV i: e r
I *019
Land Surface
X v
a!OC
Ir.tervai
g Direction of Fic.v £—r—
e c*>
g
Figure 2. The Value of Accurately Locating the Contaminated Interval
H
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SECTION II. PROCEDURE FOR ACQUIRING CORE SAMPLES
PROBLEMS WITH UNCONSOLIDATED SEDIMENTS
Traditionally, unconsolidated soils or sediments are sampled through
a hollow-stem auger with a split-spoon core barrel or a conventional thin-
walled sample tube (Figure 3). The hollow-stem auger acts as a temporary
casing to keep the borehole open until a sample can be acquired. A borehole
is drilled down to the depth to be sampled. Then the core barrel is inserted
through the annular opening in the auger and driven or pushed while rotating
tne auger into the earth to collect the sample. These tools work extremely
well in both unsaturated and saturated cohesive materials. Unfortunately,
they work poorly in ncncohesive aauifer materials, such as unconsolidated
sands.
There are two technical challenges to sampling noncohesive material
below the water table. The first challenge is to keep aquifer material out
of the annular area of the hollow stem auger. During augering, the annular
area of the hollow-stem auger is plugged with a solid drill head that pushes
the Si;'] out onto the auyer flights. To sample, the drill head is removed
and replaced with a core barrel. When the drill head is pulled out of the
auyer in consolidated sands, pressure on the aquifer sediment is reduced, and
wacer and Muidized sand rush into the annular area of the a*»yer. This
inconvenient phenomenon is commonly referred to as "heaving." The core barrel
must push through (and sample) this heaved material inside the auger before
!t reaches the undisturbed sediment underneath. When the core is recovered,
it is usually impossible to determine how much of the core is the fluidized
material and how much is an authent-c sample of the aquifer. Occasionally
the amount cf sediment in the auger is so great that the core barrel cannot
be pushed, and no saTpie can be acquired. :
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F:gur: 3. Hollow-stem auger containing a pilot assembly.
10
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The second challenge is to keep the sample m the core barrel while
it is being retrieved to the surface, when the sampling tool is pulled
out of the aquifer, the pressure holding the sairp 1 e in the tool is reduced.
Noncchesive sediment will often fluidize and dribble out of conventional
core barrels.
SPECIAL PISTON SAMPLING
Conventional practice to keep sediments out of the hollow-stem of an
auger is to fill the nollow annular column with drillinc mud. As the borehole
is advanced* the weight of the mud stabilizes the hydraulic pressure of the
aquifer. The use of drilling mid is not acceptable in gecchemical assess-
ments Decause fluids or chemicals introduced into the borehole can dram
into the aquifer and alter the geochemistry of the pore water or contaminate
the sample with foreign microorganisms. Such compromised samples cannot be
used to assess prospects for bioremediation, and there is a strong possibility
of microbial alteration of the sample during shipment or storage.
The staff of RSKERL have developed and tested new tools and protocols
that consistently provide samples of the quality needed to characterize
soil Is from underground storage tanks (Leach et al., 1983). The tools and
protocols are modifications of techniques pioneered by others, principally
researchers at the Institute for Ground Water Research, University of Waterloo,
Ontario, Canada (Zapico et al., 1987).
Instead of drilling mud, the RSKERt protocol protects the annular open-
ing of the auger with a hinged cap (ccwonly calleo a clam-shell) that folds
down and covers the open face of the auger (Figure 4). When the auger has
been advanced to the desired depth, the sampling tool is inserted into the
hollow a^ger supported by the attached drill rods until it makes contact
with the clam-shell. As the sampler is lowered, a wireline cable attached to
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Auger Head
CI
ho 1 i
Figure 4. Clam-Shell Fitted Auger Head.
12
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an interna! piston, in the sarpling tool is kept slack sc the piston will
remain in U? starting position. The augers are then lifted vertically with
a separate wirelint abcut 25 cm to open the clam-shell doors, allowing the
sampler to fall into ccntict with the sediment to be sampled before heaving
can occur. The augers are held in place with an auger fork to keep them from
slipping back down the borehole and bindi^q the sampler.
It is not presently possible to ciose the c-ai^-shel 1 doors once they
have been opened in the subsurface; therefore, if detp?r samples are
desired, the entire flight of augers is carefully removed frcm the
borehole. If the augers are rotatec' after the clam-shell is opened,
the device will be destroyed. After retrieval, the augers and the clam-shell
are thoroughly cleaned before reuse. The borehole can be backfilled to the
surface with cuttings or clean sand and then redrilled to the next desired
sampling depth. In some situations it is better to move the drilling rig a
few feet and start a new borehole. This process is slower than conventional
sampling, however, it is necessary to remove the augers in order to clean
all heave material from the interior of the augers, properly close the clam-
shell doors, and backfill the borehole. If the borehole is not backfilled,
and a deeper sample is attempted in the same borehole, the clam-shell will
open prematurely during augenng and be destroyed.
' Zapico et al. (1987) recently described a sampling device that effectively
retains unconsolidated sands inside a cannister fitted inside a core barrel.
A sliding piston inside the cannister maintains an air-tight seal on the
core. Vacuum and friction keep the core in place. This device was modified
to T.eet the special requirements of the RSK.ERL protocol (Figure 5).
The piston contains a series of neoprene seals which are mechanically
compressed, creating a positive seal of the piston inside a standard thin
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Upper. Drive
Fead with L
Threaded pin
Fead with Left \
Cable
Hardened Drive
Shoe
Cuter Core Barrel
Piston with Rubber
and Brass
i^accr
Figure 5. Waterloo Aquifer Piston Core Barrel-Scherratic
(Zapi co, 1937).
14
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walled core harrel (Figure 6). The wireline attached piston is positioned
at the end of the core barrel that wil1 be in contact with the sediment.
The wireline is pulled taut after the piston equipped core barrel has been
lowered to the bottom of the borehole. The cable holds the internal piston
stationary while the core barrel is driven into the sediment, creating a
vacuum on the sample.
The core barrel is driven by reciprocal percussion. A trip haimer
mounted on the drill rig strikes a heavy steel rod that extends from the top
of the core barrel to the surface. This rod is installed in sections as the
augers are drilled into the subsurface. Driving by percussion is preferable
to pushing the core barrel with a hydraulic ram. Percussion uses the inertia
of the sample to force it into the core barrel while a hydraulic rain forces
the sample into the tube against its natural mechanical resistance. A core
barrel driven by a ram tends to push unconsolidated materials out of the way
instead of into the barrel.
The conventional tool for retaining cores in a barrel is a core retainer
basket. This device consists of a series of flexible steel tabs that fold
flat against the core barrel while the barrel accepts the sample, then fold
out and intercept the core if it starts to slip out during retrieval.
D'jrinc, field evaluation on the difficult, unconsolidated, san^y material
at Traverse City 'SECTION IV), the piston core barrel worked very well, but
only when a core retainer basket war> used. The piston core sampler without a
core retainer basket often lost tuIf or more cf the sample before it could be
recovered. A conventional core oarrel with a core retainer basket recovered
no sample at all. The combinat.cn of the two consistently recovered more thaa
95* of the cored interval (1? boreholes, more thai) 50 cc;res).
lf>
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Drive Sho
16
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If the piston moves while the sample is being recovered, there is a
significant chance of pulling air or water through the sample and spoiling
it. All samples are retrieved using the center rod; no tension is placed on
the wireline to the piston during retrieval.
After the piston core barrel is brought to the surface, the end of the
sampler is quickly covered with a plastic bag and tightly sealed to minimize
aeration of the exposed core. The sampler is then quickly disassembled by
removing the drive cap and manually pulling the piston free from the top of
the sample tube, "hen one enc of the core barrel is connected to a hydraulic
ram r.ounted on the rig, and the core is extruded. Tne cores are collected in
wue-mouth canning jars. If possible, each jar is entirely filled with
sample. The seal on the lid of the canning jar effectively excludes oxygen
and prevents loss of volatiles.
FIELD GLOVE SOX SAMPLING
If the cores are to be used for treatability studies to evaluate the
prospects for bioremediation, they must be protected from contamination
by foreign microorganisms. If naturally-occurring microbial processes
are to be evaluated, they must also be protected from the atmosphere because
many anaerobic microorganisms are killed by oxygen.
To protect from foreign microorganisms, a core is collected by extruding
a small portion of the core, breaking off a small section to reveal an
uncontaminated face, then installing a sterile paring device onto the end of
the sample tube. This tool peels away the outer contaminated wall of the
core as the material is extruded (Figure 7).
To protect the sample from the atmcsph*jre, the sample is extruded inside
a nitfugen-f11 led glove box (Figure 8). Ihe core barrel is introduced
into the glove box through an iris port that makes a tight seal around
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2 " I. D. 5..
Paring Cvimdor
S.S. Plot ?
Figure 7. Core Paring Tool.
Flushing Vent
a
mm*
Port
Flc*..- Roquiato;
and Inaicator
Sample Tube
from Extrudi
Figure 8. Field Sampling Glove Box
18
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the barrel. The dimensions of the box are 60 X 90 X 120 cm. The box is
flushed with 1200 liters of nitrogen over a thirty minute period. Quality
as;urance tests were conducted by analyzing a series of 1.0 ml samples of
the oas vented from the box with a Varian Model 90-P gas chromatograph
equmped with a thermal conductivity detector. The concentration of
oxygen fell below 0.02%.
The glove box is prepared for sample collection by filling it with the
desired number of sterile canning jars and sterile paring devices, sealing
the box, and then purging it with nitrogen gas. To prevent oxygen
contamination when the jars are opened to receive the core lr the field
glove box, the jars are filled with nitrogen before they are brought to
the field. They are passed into a laboratory anaerobic glove box,
opened, then sealed air-tight. A slight positive pressure of nitrogen is
maintained in the box during extrusion and collection of the cores.
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SECTION III PROCEDURES TO DETERMINE THE CONCENTRATION OF CONTAMINANTS
OIL AND GREASE METHOD
EXTRACTION OF ANALYTICAL SAMPLE FROM A CCRE FOR OIL-AND-GREASE ANALYSIS
Cores are stored in glass jars with 3n inner diameter that is very
close to the diameter of the core. The depth of sediment in the j«r is very
similar to the length of core it contai In the laboratory, subsamples
for analysis are taken from the sample jar with a paste sampler (American
Scientific Products, McGaw Park, Illinois) modified with a teflon gasket
to prevent sample loss (Figure 9). The paste sampler takes * composite
of all the material from the top to the bottom of the jar, and is
representative of the depth interval in the aquifer from which the core
was extracted. Depending on the depth interval sampled, tne subsamples
weigh from 5 to 12 grams.
Each suDsample is extruded into a tared 50-ml culture tube with a
teflon-lined screw cap. Freon-113 is used to extract the petroleum
hydrocarbons. Because it has no carbon - hydrogen bonds, it is trans-
parent at the wavelengths of infra-red light used for spectroscopic
analysis of the petroleum hydrocarbons. Freon-113 is added to cover the
sample. Anhydrous magnesium sulfate (ar. amount equal to the weight of
the subsample) is added to bind any free water. Heat is given off when
water combines with anhydrous magnesium sulfate. Sometimes there is
enough heat to boil the Freon-113 which may cause loss of some volatile
organics. After mixing, the culture tube is completely filled with
Freon-113 and the cap is screwed on tightly. After ten to twenty tubes
have been prepared, they are secured in a rolling mill and tumbled slowly
end over end for l( to 24 hours. The tumbling action of the tube provides
the agitation necessary to efficiently ^*tract hydrocarbons from the sediment.
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7
Barrel
piston —
y
Teflon
yS Sleeve
Figure 9. Paste Sampler Used to Subsample Cores
21
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Then the samples are centrifuged at 2,000 rpm for 10 to 15 minutes.
The volume of the Freon-113 extract is measured in a graduated cylinder,
to allow calculation of the quantity of pet-oleum hydrocarbons in the
subsample from the concentration of fuel hydrocarbons in the extract, as
determined by infrared spectroscopy. If the extract cannot be analyzed
immediately, it is stored in a vial in a refrigerator.
INFRARED SPECTROSCOPY (itf)
A portion of the extract is transferred into a 10 mm calcium fluoride
IR cell. The sample cell and a reference cell containing Freon-113 are
placed intc the appropriate cell holders of an IR Spectrophotometer (Perkin
Elmer Model 521). The instrument is scanned from 3200 cirri to 2600 cm-1
wavenumber (see Figure 10). The spectrum for aviation gasoline has one
strong absorption peak at 2955 cm-l, while that for JP-4 jet fuel has two
strong peaks at 2955 and 2925 cm"1. The absorption peaks at 2955 and 2925
cm'l correspond to C-H stretching vibrations in -CH^ and -CH? resDectively.
The one absorption peak at 2955 cm-1 1S indicative of aviation gasoline
which consists mostly of bra°<-hed alkanes, while the two absorption peaks
at 2955 and 2925 cm-1 ere characterisec of JP-4 jet fuel, which consists
of branched and straight-c':a^ned alkanes.
If an extract is concentrated enough to deflect beyoid 1.0 absorbance
units, it is rescanned u-jing a 1 mm calcium fluoride IR cell or diluted with
Frecn-113 until the absorbance is below 0.6 units.
QUANTITATION
Star-darci5 ere prepared by adding measured aliquots of pure aviation
gasoline or JP-4 jet fuel obtained from a refinery to Freon-113 in a 100
ml volumetric flask, concentrations ranging from 0 to 3500 mg/L for the
22
\
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1R Spectrum or Aviation Gasoline
IR Spectrum of JP--1 Jet Fuel
r<3
2925 cm"1
2955 cm
2955 cm"
Figure 10. Infra-Red Spectrum of A\nation Gasoline and JP-4 Jet Fuel.
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1 m IR cell. Calibration curves for absorbance versus concentration are
prepared using the standards. Two sets of calibration curves are developed
for JP-4 jet fuel; one for absorbance at 2955 CT-1 and the other at 2')2b
cm-1. Sample calibration curves are shown in Figure 11.
The fuel content is calculated as follows:
Fuel Content = Ctm^ xV(Lj_ x f 1C00 g/kg) = mg of extractable material
w"^' kg of wet aqu'.fer materiaT
where C(mg/L) is the concentration of fuel in extract (determined
from absorbance and calibration rurve)
V(L is the volume of extract in liters, and
WtvgJ is the weight of wet sample in grams.
FUEl CARBON ANALYSIS
EXTRACTION OF ANALYTICAL SAMPLE FROM A CORE FOR FUEL CARBON ANALYSIS
In the laboratory, core subsamples for analysis are taken from the
sample jar with a paste sampler (,-igure
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240
Cop.cer.tratioa ISO
(ir.^/L)
120
60
0-j* ) ) i ) > ' 1
0.0 0.2 0.4 0.6
Absorbance
Figure ha. Aviation Gasoline in Freon (2955 cnr-)» 0-350 mg/1.
3000
2400
Concentration 1800
(r.ig/L)
1200
600
0
0.0 0,2 0.4 0.6
Absorb;inco
Figure lib. Aviation Gasoline in Freon (2955 en"1), 0-35C0 mg/1.
25
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Concent racion
(ag/L)
0.0 0.2 0.4 0.6
Absorbance
Figure- 11c. Jet Fuel in Freon-113 (2955 cm~l), 0-350 mg/1.
3200
2600
Concent r?t ion
(tt^/L) 2000
1400
800
200
Absorbance
Figure lid. Jet Fuel in Freon-113 (2955 cm"*), 200-3500 mg/1.
360
300
240
180
120
60
0
0.0
25
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Concentration
(ag/L)
360
300 --
240 --
180
120 --
60 -•
0.0
0.6
0.2 0.4
Absorbance
Figure lie. Jet Fuel in Freon-113 (2925 cm~l), 0-350 mg/1
3200 -•
Concent rat ion
(mg/L)
2600 r
2000 ••
1400
800 ••
2U0
0.0
o.;:
0.4
o. *
Ah rb "n'lL e
Figure 11f, Jet Fuel in Freon-113 (2925 cm**), 200-3500 mg/1
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3AS CHROMATOGRAPHY
One microht;?- of the dried extract is injected intc a gas chroniatograph
equipped with a wide-bore capillary column (J & W Scientific DB-5, 15 m x
.53 mm ,.d., 1.5 min film thickness). The injection is done in a splitless-
mode with a solvent purge at C.7 minutes. Eoth the injector and the
flame ionization detector (FID) are kept -»t 300"C. The carrier gas is
high-purity helium supplied at 9 ipl/ntnute. Tne make-up gas for the F10
detector is high-purity nitrogen s :¦>;>' led at 21 ml/minute. The 6C rven
is cooled cryogemca1ly by liquid nitrogen. The temperature program is
10#C for 3 minutes, then a "linear increase of 10*C/minute to ??5'C, then
225°C for 2 minutes.
QUANTITATION
JP-4 jet fuel ana aviation gasoline obtained from a refinery are
used to prepare standards by adding measured aliquots of JP-4 jet fuel or
aviation gasoline to methylene chloride. A calibration curve is prepared
by analyzing the standards and summing the areas o* the major peaks for
each standard concentrat ion. Sample curves are shown in Figures 12 and
13.
Retention tixes of the major peaks used for each calibration standard
o." sample analyzed are determined.
COMPARISON OF THE METHODS
The fuel carbon method and the oil and grease method compare favorably,
even though t-h^v are basea on entirely different principles (Powell et
a!., 1983). The fuel carbon analysis is preferred at R.S. Kerr
Laboratory because it also provides information on the concentration of
aiky^berzenes in waste oils.
I
?P
I
i
i
1
¦ %
-------
0-^- 1 1 i 1 1
2 4 6 8 10 12
Avgas Concentration in pg
Figure 12. Standard Calibration Curve for Aviation Gasoline
29
-------
50 -
40
CO
o
X
o
o
<
o
a.
>1
10 -
R = i.000
JP-4 Concentration in j:g
Figure 13. Standard Calibration Curve for JP-4 Jet Fuel.
30
-------
SECTION IV. FIELD DEMONSTRATION OF SAMPLING AND ANALYTICAL PROCEDURES
IN DESIGNING A BIOREMEDIATI ON
In 1969, a spill of aviation gasoline from an underground storage
tank at the U.S. Coast Guard Air Station at Traverse City, Michigan,
contaminated a shallow, sandy, water-table aquifer. Ground water movino
through the spill produced a large plume that eventually moved off the
base and ruined a large number of domestic water wells in a residental
area ("igure 14). The spill contained at least 25,000 gallons of aviation
gasoline, which drained to the water table 16 feet below land surface,
then spread laterally in the capillary fringe to contaminate a section of
aguifer about 80 yards in diameter (Figure 15).
OESIGN OF THE EXPERIMENT
In 1083 the U.S. Coast Guard and the U.S. EPA installed a pilot
scale study of bioromediation in the area of the original spill. The
alkylbenzenes are the object of the regulatory concern, and the bio-
remediation will be finished when their concentration is brought below
5 ug/liter, as specified in a consent decree between the Michigan Depart-
ment of Natural Resources and the U.S. Coast Guard.
Cores were acquired from the source area to determine the vertical
and horizontal extent of contamination, the concentration of total hydro-
carbons in the contaminated interval, and concentrations of individual
alkylbenzenes. The aviation gasoline was composed primarily of branched-
chau, alkanes. The material spilled at Traverse City was 38% 2,2,4-tn-
methylpentar.e; 15% 2,2,5-trimethylhexane; 14% 2,3-dimethylpentane; 1;.%
2,4-dimethy!hexane; 7% 2,3-dimethylhexane; and 5% 2,4-dimethylpentans.
Hnly 10% of the original spill was alkylbenzenes.
31
-------
-------
U.S. COAST GUARD
AIR STATION
INDUSTRIAL
PARK
HANGAR
RESIDENTIAL
AREA
1.0 km
Figure 14. Former Extent of a Plume of Contamination Produced by a Spill
of Aviation Gasoline on the U.S. Coast Guard Air Station at
Traverse City, Michigan.
32
-------
N
50 R
DEMONS T RATION
AREA
PLUME
ORIGINAL
SOURCE
FAILED
FLANGE
HANGAR
ADMIN.
BUILDING
SCALE ^
50 m
Figure 15. The Area in a Spill of Aviation Gasoline Selected for a
Field Demonstration of In Situ Biorerrediation.
33
-------
The gasoline was confined to a narrow interval oetween 15 and 17 feet
below the land surface (Table 1). This interval corresponds ciosely with
the seasonal high and low water table at the site.
Table 1. Vertical distribution of contamination
SO feet down gradient from the injection wells
Cepth interval
'feet below surface)
puel Hydrocarbons
(mg/kg aquifer)
15.1 - 15.5
15.5 - 15.8
15.8 - 16.?
Id,2 - 16.5
16.5 - 17.?
17.2 - 17.5
18.0 - 18.3
<11
39
23 70
8400
62*
<15
<13
This information was used to identify the most-contaminated flow oath
tr.rough the spill. A series of miniature monitoring wells was installed
along and below the most-containinated flow path (Figure 16). These wells
were constructed of 3/8 inch stainless steel tubing connected to a
stainless-steej screen that was 6.0 inches long. The screens were
constructed from stainless steel wire with a me^h width of 0.5 irm.
The wells were connected to cylindrical sample traps wUh a volume of
300 Til, During sampling, a vacuum was applied to the trapi. At least
2.0 'iters of water were extracted through the weT and trap to comp^tely
flush them, then a valve was closed between Lh? wei1 and trap, and the
trap drained into tne sample container through a second valve.
A set of infiltration wells was installed to perfuse the contaminated
area .vi;;h mi'.era! nutrients, ar.d oxygen or hydrogen peroxide. This water
contained 330 mg/liter ammonium chloride, 190 mg/liter disodiun: phospnete,
34
-------
ELEVATION IN
FEET ABOVE MSL
INJECTION
WELLS \
BD-31
BD-50
610-
605-
600
ZONE OF 04
CONTAMINATION
WATER TABLES
595 -
2-24-88
3-4-88
3-1 1-88
590-
HORIZONTAL SCALE IN METERS
Figure 16. Vertical Cross S^c^io1", or the Bicremediation Demonstration Area.
-------
and 190 mg/liter potassium phosphate. The temperature was 11-12" C, and
the pH near neutrality. The flow of chemically-amended water was
10 gallons/mmute. Clean water from another part of the aquifer was
infiltrated at 30 gallons/minute in a deeper set of wells. This water
was not amended with nutrients or oxygen, it merely served to steepen
the hydraulic gradient and increase the seepage velocity of the amended
water through the contaminated interval.
The seepage velocity of the injected water in the aquifer averaged 5 to
9 feet per day (Table 2). Tracer tests were conducted for each monitoring
well to determine the actual seepage velocity along the flow path to that
particular well (see Figure 17 for typical breakthrough data of chloride
as a tracer).
Table 2. Seepage velocity of oxygen, ammonium ion, phosphate, and
chloride to monitoring wells.
Well Tracer Depth on Figure 7. Depth #2 is in the most
contaminated interval.
1 2 3 4 5
Apparent velocity (ft/day)
3331- 31 feet from
infiltration wells
Chloride (03/03)
5.5
5.5
8.9
Chloride (12/88)
8.6
8.0
not done
Oxygen (03/88)
NBT*
4.4
9.2
Ammonia (03/38)
3.9
3.9
6.2
Phosphate(03/83)
3.6
3.7
6.2
503- 50 feet from
lnfl1tratlon wel 1 s
Chloride (03/33)
4.3
6.0
5.5
9.2
12.6
Chloride (10/38)
NST
7.5
8.9
16.0
18.4
Oxygen (03/38)
NBT
NBT
N3T
9.2
12.6
... i m \
Mil IIIU' ' » O \ 'x -J > U )
2.3
2.1
3.3
6.0
10.0
Phosphate(03/88)
1.5
2.1
2.9
6.0
9.2
* Breakthrough not observed during the tracer test
36
-------
o
200 ~
Chloride Breakthrough
en 50B-2
150.
100 Q
50
o
a a
o a cPq c^aaa aoo °Dn
,—r^-1, „ | 1 1 (—b_LL| 1 1 1 1 1 ( 1
40 80 120 160 200 240 280
Time: hours
Figure 17. Breakthrough Curve for Chloride in the Flow Path from the Injection
Wells to Monitoring Well BD 508-2 in the Bioremediation Demonstration
Area.
-------
Notice that the velocity of water in the most contaminated interval
(level 2).is much less than the velocity in the cleaner part of the
aquifer only a few feet beneach (1e\e1 4 and 5), Also notice that
ammonium ion and phosphate move at about half the velocity of water
in this aquifer.
Injection began the first week of March, 1988. The system was first
acclimated to oxygen, then switched to hydrogen peroxide. The schedule
of application of oxygen and hydrogen peroxide is presented in Figure 18.
The concentration of hydrogen peroxide was increased slowly, to allow time
for microbial acclimation to concentrations of hydrogen peroxided that are
generally toxic to most heterotrophic bacteria.
ESTIMATE OF OXYGEN DEMAND REQUIRED FOR REMEDIATION
The concentration of total petroleum hydrocarbons in the most contaminated
interval near the infiltration wells was near 300 mg/kg. The highest measured
concentration of total hydrocarbons near a monitoring well 31 feet down
gradient from the injection wells is 8,400 mg/kg (core 50AE4 in figure 10
and 11). The highest measured concentration 60 feet down gradient is
6,500 mg/kg (core 50114 in figure 19 and 20). The average of cores 50AE4
and 50114 (7,500 mg/kg) was taken as the best estimate of the concentration
of total petroleum hydrocarbons in the most-contaminated interval between
the monitoring wells at 31 and 50 feet. The interval between the injection
wells and the monitoring wells could not be cored because access was
blocked by a sanitary sewer line. The most conservative estimate would
consider the entire interval between the injection wells and the monitoring
well at 31 feet to be contaminated a: 7,500 rrg/kg. The most liberal
estimate would consider the interval to be contaminated at 300 mg/kg. An
arbitrary intermediate estimate we *d average 7,500 and 300 mg/kg. The
-------
400
350
300
250
200
150
100
50
* "is ,» «
s * ^
H O
dm I
o.
'W^'jm'nj.' 'ly'OR'
. \ ^
\ <;
r \
¦i;
< S *V
J6> ->
* "N. ^ ~ y
av4 ^ « r \ <
V»
}"• -> X<^N ^,^-v ,S
\ ±*r < „ I
* <• ~»¦*•<* +
^ ** v.\ •<---• ». .
• ,S ^ ... .. . V.SW. ..s* •>% \>i/> ¦
v* \s ^ £-••
£-Vv>>,v'£'S*/« - -
-'•
" :*ie< f
... .
* K NV v.' .Vy~
V"* *
>c<
x* ? \
c.
S ••*•
i>
w
N. ^
J-+
50 100 150 200 250 300 350 400 450
Julian Date
Figure 18. Schedule of Application of Oxygen and Hydrogen Peroxide-
Julian Date 1 is January 1( 1988.
39
-------
£a»
o
ELEVATION IN ^INFILTRATION
FEET ABOVE MSLyf WELLS
BD-31
B0-50-a
S 15-)-
610
605
600
595-
590'
JMIer tar> f
S0AE5
OAQ3
50AE4
--It; 50Tj3_
ZO?!E OF
/CONTAMINATION
CD
"i>"sori4"
^ 50AR4
._ci_lru
50D18 SOA3
Figure 19.
Relationship Between Core Samples and Monitoring Wells m the
Bioremediation Demonstration Area.
-------
BORDER OF DEMONSTRATION AREA
SCALE
N
5m
DIRECTION
OF y
FLOW' -
oOAE and 50AO-
SOT and BD-3I-
¦BD- SOB
/rSOI and SOAR
* f50AC /^50A
t //
¦INFILTRATION
WELLS
HANGAR
ADMIN.
igure 20, Hap of the Relationship Between Core Samples and Monitoring
Wells in the 8t©remediation Demonstration Area.
n
-------
oxygen demand alc.ig tr_ most contaminated interval was calculated for all
three estimates.
The empirical chemical formula for aviation gasoline is CH? 2 (Powell
et al., 1988). The empirical formula for the alkylbenzene fraction is
CHl.l- The oxygen demand for microbial respiration of total fuel hydrocarbons
was estimated assuming the following stoichiomotry:
CM2,2 + 1-55 Op * CO? + Hp.pOl.l
The oxygen demand of the alkylbenzene fraction alone was estimated from:
C^l.l + 1-28 02 "*• COp f 0.55 H?0
The theoretical oxygen demand for aviation gasoline is 3.5 mg/mg, the
demand of the alkylbenzene fraction is 3.1 mg/mg.
To calculate the theoretical oxygen demand of the hydrocarbons in a
segment of a flow path, the hydrocarbon content (mg hydrocarbon/kg
aquifer) was Multiplied by the bulk density of the sediment (2.0 kg/liter)
and divided by the porosity of the aquifer (0.4 liter pore space/liter total
volume) to determine the quantity of hydrocarbon exposed to each liter of
pore water in the segment. The quantity of hydrocarbon was multiplied by
its oxygen demand to estimate the quantity of oxygen that must be delivered
to each liter of pore water in the segment.
The interval from the injection wells to the monitoring well 31 feet
down gradient was considered one segment. Th€ demand in the flow path to
the monitoring well 50 feet down gradient was estimated as the weighted
average of the demand in the segment from the injection wells to 31 feet,
and in the segment from 31 to 50 feet.
4 2
-------
PERFORMANCE OF THE DEMONSTRATION
The interval between the injection wells and the monitoring wells was
considered remediated when detectable oxygen broke through and alkyl-
benzenes disappeared, Compare Figures 21 and 22. The interval to the
monitoring well at 31 feet was remediated after 220 days (Julian Date
281), a,id the interval to the monitoring well at 50 feet was remediated
after 270 days (Julian Date 331).
The seepage velocity (as determined by the tracer tests) was multiplied
by the concentration of oxygen or hydrogen peroxide n the injection wells
{Figure 18) to determine the instantaneous flux of oxygen or hydrogen peroxide-
along the flow path. T!^e cumulative flux at the time of remediation was
considered the actual oxygen demand for remediation (Table 3).
The aquifer was purged of alkylbenzenes very quickly. Aviation
gasoline is composed primarily of branched-chain alkanes. Only 10% of
the original spill was alkylbenzenes, The quantity of oxygen and hydrogen
peroxide r £ Q »r n u to remove al kyl ueiiz ernes fru«t iny wki ib ayreed ciorcly
with the projected oxygen demand of the alkylbenzenes alone (Table 3).
This may, to some extent, be fortuitous. Some of the alkylbenzenes
must have been washed from the source area by simple physical weathering.
Some of the alkylbenzenes may have been removed by anaerobic biological
processes before the front of oxygen swept through, l»!ater from anaerobic
regions of the demonstration contained significant concentrations of volatile
fatty acids and was visibly turbid with microorganisms. In any case, the
the flow p^ths to the monitoring wells at 31 and 50 feet from the injection
wells were remediated when a small fraction of the oxygen demand of the
spill had been supplied.
43
-------
O)
c
o
m
>s
X
O
"U
Q>
>
O
(0
-500
-300
- 200
• 100
Julian Date
Figure 21. Changes in Concentration of 41kylbenzenes and Oxygen in
Monitoring Well BO 31-2 During BiorcT-ediation.
44
-------
I5>
o>
a
oj
>»
O
"O
o
«5
vj
600
- 500
400
300
200
100
Qi
Ol
3
X
H
m
Q
O
400
Julian Date
Figure 22
Chanqes in Concentration of AUylbenzenes and Oxygen
in Monitoring Well BO 50B-2 During bio
-------
Table 3. Estimated and actual oxygen demands of the most contaminated interval
in the aviation gasoline spill at Traverse City, Michigan.
-e»
Oxygen or Hydrogen Peroxide Demand along Flowpaths
to Monitoring Wells 31 and 50 feet down gradient
of the infiltration wells
Conservative Moderate Liberal
Estimate Estimate Estimate
31 50 31 50 31 50
feet feet feet feet feet feet
—(mg oxygen/liter pore water)
Estimated demand based on:
Total Fuel Hydrocarbons 130,000 130,000 68,000 92,000 5,000 53,000
Alkylbenzene content only,
when sampled in 8/87.*
Alkylbenzene content only,
when sampled in 3/88 just
before the start of the?
demonstration.**
Actually delivered by 10/88.
Corresponds to Julian Date
10,000 10,000 5,000
1,100 1,100 593
3,000 3,000
300
7,000 400 4,000
800 45 460
~based on analysis of core 50114 (Table 5) assuming 7,500 mg/kg total hydrocarbon
**based on analysis of core 50T3 (Table 5} assuring 7,500 mg/kg total hydrocarbon
-------
This selective removal of alkylbenzen^s may result from their
relatively high water solubility. If the system follows Raoult's Law,
the expected concentration of an individual hydrocarbon in water in
equilibrium with the gasoline can be estimated by multiplying its water
solubility by its mole fraction in the gasoline.
The expected concentration of toluene in water in equilibrium with
tte fuel was 15 mg/liter. As shown in Figure 23 the measured concentration
of toluene has been as high as 32 mg/liter. The expected concentration
of 2,2,4-tnmethylpentane is only 0.2 mg/liter. Actual measured concen-
trations are m the anaerobic zone of the demonstration area range from
O.n* to 0.0? my/liter. The aUylbenzenes may have been more available
to the microorganisms.
CONTRIBUTION OF WATER WASHING
A significant fraction of the alkylfcenzenes may simply be washed
out of the demonstration area by the f«ow of water, instead of being
destroyed by biodegradaUon. The significance of this physical weathering can
be evaluated by comparing the retardation factor of each alkylbenzene
in the most-contaminated interval to the number of pore volumes of water
that have been delivered to a particular point.
The ratio of the seepage velocity of water to the apparant seepage
velocity of an individual alky^enzene is termed the retardation ratic.
This retardation ratio is equal to 1.0 plus the ratio of the mass of the
aikylbenzene in immobile gasoline to the mass in the flowing water.
The distribution of the a'kylbenzene between gaso^ne and water in the
aquifer is estimates from RaouU's taw, by dividing the distribution of
the? alkylbenzene between the pure compound and water (its specific gravity
47
-------
TOLUENE ELUTION FROM A
CONTAMINATED TRAVERSE
CITY CORE
•fc.
CO
CONCENTRATION
mg/liter
35 x
30
25
20
15
10
V.k';,,-
>V{ ,
; »:r, I'j'i-
¦"'i'l' -jiiV
¦i>fe <3
.iS1/ *
V> \' J."
• /» 'n-vA*' .
'• ;W
IM
u
V J "k'
•;v>r.
V.'-'-tl"
ft
6
POP.E VOLUf 1FS
Figure 23. Comparison of the Concentration of Toluene leached From Contaminated
Aquifer Material in the First Pore Volume to Concentrations Leached in
Subsequent Pore Volumes.
-------
divided by its water solubility) by the ratio of water to gasoline in the
aquife^. These calculations can be done a number of diffe-ent ways. For
convenience, we will express units as mass of organic compound per unit
vokme of the phase that contains it.
If the most-contaminated interval contains 7,500 mq/kg total
petroleum hydrocarbons, and its bulk density is 2.0 kg/1 iter, then
the most-contaminated interval contains 15,000 mg petroleun hydrocarbons
per liter of aquifer. (Note: The proper unit for volume should be cubic
decimeter. In formal usage the liter is a unit for capacity). The
>pecific gravity o* the gasoline is 0.76 (Smith et a1.» 1931), therefore
the most contaminated interval of the aquifer contains 20 ml gasoline
per liter of aquifer. The porosity of the aquifer, as determined by
weighing cores and then measuring the weight loss on drying,
is 3S0 ml pore space per liter of aquifer. If 20 ml of the pore space
in eac.'j liter of aquifer is gasoline (Figure 24), the remaining 360 ml
must be occupied by water. The volumetric ratio of water to gasoline is
360 to 20, or 18 to 1,
This approach for comuputmg retardation can be evaluated with data
from a column test {Bouchard et al., 1989). Core material from the demon-
stration area was packed into a column, washed with water to remove
all the alkylbenzenes, and then a pulse of alkylbenzenes in solution was
flushed through the column. The core material used to construct' the
column contained 1,340 mq/kg total"petroleum hydrocarbons, corresponding
to a water to gasoline ratio of 112 (vol/vol).
49
-------
Column with
contaminated
Supply
CaCI
Valv«
Syrlng* pump
Valve
LEACHING COLUMN CONFIGURATION
Figure 24. Laboratory Column Used to Estimate the Leaching of Alkylbenzenes
from Contaminated Aquifer Material.
-------
Table 4. Predicted retardation ratios for selected hydrocarbons in a column
study (Figure 25) and in the field demonstration.
Compound
Specific
Gravity
(g/1iter)
j. Solubility
(g/liter)
Volume Water
Volume Gasol me
in in
Predicted
+ 1.0 - Retardation
Ratio
in in
Aquifer
Column
Aquifer Column
Benzene
878
1.78 G 2G°C
18
112
28
5.4
Toluene
867
0.47 @ 16°C
18
112
103
17.4
o-Xylene
880
0.175 0 20°C
18
11?
280
46
p-Xylene
864
0.167 § 25°C
18
112
290
47
ro-Xylene
360
0.198 @ 20°C
18
112
240
40
E thylbenzene
867
0.142 @ 15°C
18
112
340
56
l,2,4-Tri~
830
0.057
18
112
860
140
methyl benzene
Specific Gravity and Solubility from Verschueren (1983) and Smith et al. (1981)
The retardation ratios (Table 4) predicted for the column study
(17.4 for toluene 46 for _o-xylene» 56 for ethytbenzene, and 140 for
1,2,4-tnmethylbenzene) are in acceptable agreement with the laboratory
data (Figure 25). There is some justification to using tne predicted
retardation ratios to estimate the relative contribution of water washing
and biorestoration in the field scale demonstration
Based on the chloride tracer test, 3.6 days were required to move one
pore volume of water frcn the injection wells to tne monitoring well 31
feet down gradient, and 6.7 days to move one pore volume to the monitoring
well 50 feet down gradient. By October of 1983 (Julian Date 300 m
Figures ?1 and 22), 67 pore volumes had moved past the monitoring well
31 feet down gradient, and 35 pore volumes had moved past the monitoring
well 50 feet down gradient,
51
-------
Miscible Displacement Run 1
"44Z3 Core"
U1
ro
C/Co
1 .20t
0.96
0.72
0.48
0.24
0.00
0
Toluene
o-Xylene
• "Jn
I" -6° i.
¦ °°
_ Cr.O ¦
¦¦¦
'BO • O
BOO°« Ll"Br.
-------
After cojnparmq the number of pore volumes of water delivered along
the most contaminated interyal to the predicted retardation ratios of
individual alkylbenzenes in the leld demonstration (Table 4), it ss
evident that benzene could easily have been removed by wate. -ashing, and
that a fraction of the toluene may have been removed, but hardly any
removal of the xylenes, ethylbenzene, or trimethylbenzene can be expected.
CONFIRMATION OF REMEDIATION
The soi11 was cored in August 193? to provide information to design the
demonstration, then cored again in March 1988, just before the demonstration
began, to define the initial conditions. Compare cores 50114 and 50T3 in
Table 5 and Figure 19. The proportion of alkylbenzenes in the spill
declined modestly over the time interval. This was probably due to
anaerobic microbial degradation as discussed earlier.
Shortly after the breakthrough of oxygen in monitoring well BD 31-2,
the area near the monitoring well was cored and analyzed for alkylbenzenes
and total fuel hydrocarbons. Compare cores 50AE4 and S0AF5 in Table 5
and Figure 19 to Cores 5QT3 and 50114. The aliphatic hydrocarbons remained
at their initial concentration, but the alkylbenzenes were below the
analytical detection limit {Table 5). It is not surprising that the
non-aromatic fraction of the spill remained in the aquifer. A very minor
fraction of their oxygen demand had been supplied when the aquifer was
cleansed of alkylbenzenes (Table 3).
When the region near BD31-2 was cored in March of 1989, almost
all the petroleum hydrocarbons had been removed, including the branched-
chain alkanes. Compare core 50AQ3 to 50T3 and 50114 m Table 5 and
Figure 19.
53
-------
Table 5. Changes in concenr.ratirns of alkylbenzenes and total fuel
hydrocarbon in core ma:enal during bio^emediation of an aquifer
contaminated with aviation gasoline.
Date Oil and Fuel Ethyl-
Grease Hydro- Benzene Toluene benzene Xylenes
Core Number Carbon
mg/kg wet sample
Background conditions in an unweathered part of the spill area.
June, 1988. See Figure 3 for location.
50R6 12,150 1.0 107 57 218
50R7 5,220 1.0 170 24 100
Preliminary sampling used to design the bioremediation project near
monitoring well 5D-31-2, August 1987. See Figures 1^ and 20 for location.
50A3
4,310
5,590
0.6
235
33
121
50114
4,130
6,500
0.3
544
12
48
50018
1,130
2,500*
0.7
112
11
39
Sampled after four months of perfusion with mineral nutrients and oxygen,
June, 1988.
50T3 3,330* 1.4 1 7.3 23
Sampled after eight months of perfusion with mineral nutrients and oxygen,
October, 1983.
50AE4 8,400 <0.3 <0.3 <0.3 <0.3
50AE5 2,370* <0.3 <0.3 <0.3 <0.3
Sampled after 12 months of perfusion with mineral nutrients and oxygen,
March, 1389
50AQ3 9 <0.3 <0.3 <0.3 0.1
Sampled after 12 months of perfusion with oxygen and mineral nutrients
March, 1989. Cxygen had not reached this part of the aquifer.
50AR4 3,100* 1.5 <0.3 9.2 36
*these cores included some uncontaminated material.
54
-------
core taxen from a region in
was depleted showed an interesting
even though significant quantities
It is difficult to rationalize the
some mjrely physical mechanism.
the demonstration area where oxygen
pattern. Toluene is depleted in 5CAR4,
of benzene and ethylbenzene remain,
selective removal cf toluene through
55
-------
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Bouchard, D.C., C.6. Enfield, and M.D. Piwom. 1989. Transport Processes
Involving Organic Chemicals. Soil Science Society of America and Ameri-
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Leach, Lowell E., F.P. Beck, J.T. Wilson, and D.H. Kampbell. 1988.
Aseptic Subsurface Sampling Techniques for HoHow-Stem Auger Drilling.
Proceedings of the Second National Outdoor Action Conference on Aquifer
Restoration, Ground Water Monitoring and Geophysical Methods, Vol. 1
pp. 31-51.
Powell, R.M., R.W. Callaway, J.T. Michalowski, S. A. Vandegnft, M.V. White,
D.H, Kampbell, B.E. Bledsoe, and J.T. Wilson. 1988. Comparison of Methods
to Determine Oxygen Demand for Bioremediation of a Fuel Contaminated
Aquifer. Intern. J. Environ. Anal. Chem., Vol. 34, pp. 253-263.
Snith, J.H., J.G. Harper, and H. Jaber. 1981. Analysis and Environmental
Fate of Air Force Distillate and High Density Fuels. Air Force Engineering
and Services Center, Final Report, October 1981.
Vanc'egrift, Steve A., and Don H. Kampbell. 1988. Gas Chromatographic
Determination of Aviation Gasoline and JP-4 Jet Fuel in Subsurface Core
Samples. Journal of Chromatographic Science, Vol, 26, pp 566-569.
Verschueren, Karel. 1983. Handbook of Environmental Data On Organic
Chemicals, second edition. Van Nostrand Reinhold Company.
Wilson, John T., and Don H. Kampbell. 1989. Challenges to the
Practical Application of Biotechnology for the Biodegradation of
Chemicals in Ground Water. Presented before the Annual Meeting of the
American Chemical Society, Division of Environmental Chemistry,
Dallas, Texas, April 9-14, 1989.
Zapico, Michael M., S. Vales, and J.A. Cherry. 1987. A Wireline Piston
Core Barrel for Sampling Cohesionless Sand and Gravel Below the Water
Table. Ground Water Monitoring Review, Vol. 7, No. 3, pp. 74-82.
56
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TECHNICAL REPORT DATA
(fftjir r?aJ /rti'rui in>n\ <).•* the rut-ru- b:fore inmpivUn^
» REPORT NO
LW600/?-tW/04i ORGANIZE1 JN NAME ANDADL)"£SS
'i.S. Environmental Protection Agency
5 REPORT DATE
Ju^y 1989
6 PERFORMING ORGANIZATION COC't
fl PERFORMING ORG ANIZ A T . ON REPORT NO
N.S.I. Techno^ng., Services, Inc.
R.S. Kerr Environmental Research Laboratorv
P.O. Pox 1198, Ada, OK 7-1820
W SI'CNStlMINC. A',F NC> NAMl ANU AOORfcSS
Aul ert S. Kerr- [nv ironnienta 1 Research Laboratory
U.S. Environmental Protection Agency
P.O. Box 1193
Ada , OK 748^0
Ada
10. PROGRAM fcLfcMfcNT NO.
ADVJ01A
rr'CONT MAC f. GRANT NO
In-house
13 1 v»• | OF ntPont ANU I'tflUli
r ir>a 1 Report U^
14. SPONSORING AGENCY COOE
FPA/600/15
COVlUO
85-19139
15 Guri'l L Mt N r A R V Nurts
Project Officer: John T. Wilson
FTS: 7'13-2259
16 A y b r H A c I
This report presents a systematic approach for the design of in ?itu bioremediation
of hydrocarbon contamination in ground water from the determination of the total
quantity of hydrocarbons in the aquifer to the utilization of that information in an
actual field bioremediation demonstration. This report explains why the total
quantity of h>drocarbons in an aquifer can only be determined by collecting cores. A
procedure to acquire cores from ct contaminated aquifer is described. Ihe procedures
described in the report were field-tested in designing a demonstration of the
bioremediation of an aviation gasoline leak. The performance of the demonstration was
consistent with the expected performance based on the preliminary site
characterization using the described procedures.
DESCRIPTORS
kr v wonos and docum*ni anai
in*: i Mt «s off n iNUto itnv, i cos a r i I icM/C.roup
18. Oi 3 I Ft I y U MON ST 4 f F Mf N
RELEASE ro PUBLIC
1'> SFC*Urt!T> ','l.AV; ./l»M Vc/'.-rf;
UMCLASSU I ED
ro S F C J n • T *»" CLASS ""Him
u'K.LAssinrn
71 NO O* f'AGf
w
72 rnic^ *
EPA Form 2220-1 (*'•» 4-77) rncviO'jj eoH'On u op*jlk w ^
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